Introduction:

In recent years, the consumption of ultraprocessed foods in schoolchildren has increased and this has been linked to an increase in the prevalence of childhood obesity.

Objective:

To calculate the size of the effect of a nutritional intervention on food consumption in basic education schoolchildren in Reynosa, Tamaulipas, Mexico.

Materials and methods:

Longitudinal study, with a sample of 309 schoolchildren from 12 public elementary schools; two groups were formed: intervention (IG) and control (CG) with a follow-up of one year. Measurements of weight, height and waist circumference were made. To evaluate the foods included in school lunch, a food registry was used before and after the intervention and they were characterized as recommended and not recommended. The effect size (ES) was calculated using the Hedges’g statistic.

Results:

At the end of the study in both groups, water consumption increased, however the ES was big in the IG (ES=0.84); while in the CG it was moderate (ES=0.50). In the IG, a small reduction in the consumption of processed meats was observed (p=0.004; ES=0.28), sweet cereals (p=0.001; ES=0.36) and sweetened nondairy beverages decreased (p=0.001; ES=0.49); while the CG showed a small increase in the consumption of fast food and Mexican appetizers (p=0.001; ES=0.46).

Conclusions:

In the IG showed a TE small decrease in consumption of processed meats, sweet cereals, and sweetened non-dairy beverages. It is necessary to design strategies that promote the consumption of recommended foods. Arch Latinoam Nutr 2022; 72(3):154-162.